The fact that OH has always been a "swing" state, with a lot of union people, that tends to go toward more moderate (or moderately-perceived) candidates like Bush (who barely won OH, twice.) Our state offices and Senators are nominally conservative (Kasich, Portman, DeWine) but more conservative guys like Ken Blackwell don't do well. (Jordan is an exception and has a great district).
Voter registration is skewed solidly Dem.
Cleveland dominates the state, somewhat offset by Cincy. But in recent elections Columbus has trended Dem.